Added optional Lua lexer support.

This support is disabled by default and must be enabled via compile-time option.

1 files changed, 54 insertions, 0 deletions

diff --git a/lexlua/myrddin.lua b/lexlua/myrddin.lua
new file mode 100644
index 000000000..abe5b601a
--- /dev/null
+++ b/lexlua/myrddin.lua
@@ -0,0 +1,54 @@
+-- Copyright 2017-2018 Michael Forney. See License.txt
+-- Myrddin LPeg lexer.
+
+local lexer = require('lexer')
+local token, word_match = lexer.token, lexer.word_match
+local P, R, S, V = lpeg.P, lpeg.R, lpeg.S, lpeg.V
+
+local lex = lexer.new('myrddin')
+
+-- Whitespace.
+lex:add_rule('whitespace', token(lexer.WHITESPACE, lexer.space^1))
+
+-- Keywords.
+lex:add_rule('keyword', token(lexer.KEYWORD, word_match[[
+  break const continue elif else extern false for generic goto if impl in match
+  pkg pkglocal sizeof struct trait true type union use var while
+]]))
+
+-- Types.
+lex:add_rule('type', token(lexer.TYPE, word_match[[
+  void bool char byte int uint int8 uint8 int16 uint16 int32 uint32 int64 uint64
+  flt32 flt64
+]] + '@' * lexer.word))
+
+-- Identifiers.
+lex:add_rule('identifier', token(lexer.IDENTIFIER, lexer.word))
+
+-- Comments.
+local line_comment = '//' * lexer.nonnewline_esc^0
+local block_comment = P{
+  V'part' * P'*/'^-1,
+  part = '/*' * (V'full' + (lexer.any - '/*' - '*/'))^0,
+  full = V'part' * '*/',
+}
+lex:add_rule('comment', token(lexer.COMMENT, line_comment + block_comment))
+
+-- Strings.
+lex:add_rule('string', token(lexer.STRING, lexer.delimited_range("'", true) +
+                                           lexer.delimited_range('"', true)))
+
+-- Numbers.
+local digit = lexer.digit + '_'
+local bdigit = R'01' + '_'
+local xdigit = lexer.xdigit + '_'
+local odigit = R'07' + '_'
+local integer = '0x' * xdigit^1 + '0o' * odigit^1 + '0b' * bdigit^1 + digit^1
+local float = digit^1 * (('.' * digit^1) * (S'eE' * S'+-'^-1 * digit^1)^-1 +
+                         ('.' * digit^1)^-1 * S'eE' * S'+-'^-1 * digit^1)
+lex:add_rule('number', token(lexer.NUMBER, float + integer))
+
+-- Operators.
+lex:add_rule('operator', token(lexer.OPERATOR, S'`#_+-/*%<>~!=^&|~:;,.()[]{}'))
+
+return lex